『新东方在线托福阅读』为托福考生准备了ETS托福TPO/Official 28 Passage 3阅读练习：Why does the author mention that “dogs recognize each other via smell”?真题题目及答案解析，TPO/Official 28 Passage 3阅读原文范文音频翻译

托福TPO/Official 28 Passage 3阅读原文Why does the author mention that “dogs recognize each other via smell”?题目答案及解析-新东方托福官方网校手机版

雄鹿擦痕是林地中出现白尾鹿的一个明显标志。

A conspicuous sign indicating the presence of white-tailed deer in a woodlot is a buck rub.

雄鹿用鹿角剥去一棵小树的树皮（外层），以此来制造雄鹿擦痕。

A male deer makes a buck rub by stripping the bark (outer layer) of a small tree with its antlers.

当完成后，雄鹿擦痕对我们来说是一个明显的视觉信号，大概对该地区的其他鹿也是如此。

When completed, the buck rub is an obvious visual signal to us and presumably to other deer in the area.

摩擦通常位于树皮光滑且直径小（16-25毫米）的树上，（高度为）鹿的肩部高度（离地面一米或更少）。

A rub is usually located at the shoulder height of a deer (one meter or less above the ground) on a smooth-barked, small-diameter (16–25 millimeters) tree.

小红枫光滑的树皮使这种树种非常适合美国中东部森林中的雄鹿产生擦痕。

The smooth bark of small red maples makes this species ideal for buck rubs in the forests of the mid-eastern United States.

成年公鹿通常在夏末或初秋时产生摩擦，此时它们的鹿角正在脱落外部绒层。

Adult male deer usually produce rubs in late summer or early autumn when the outer velvet layer is being shed from their antlers.

摩擦是在繁殖季节（发情期）前一到两个月产生的。

Rubs are created about one to two months before the breeding season (the rut).

因此，在很长一段时间里，生物学家认为公鹿不仅用雄鹿擦痕来清洁和擦亮鹿茸，而且还为随后的发情期间的雄鹿间的搏斗提供了练习机会。

Hence for a long time biologists believed that male deer used buck rubs not only to clean and polish antlers but also to provide practice for the ensuing male-to-male combat during the rut.

然而，生物学家也注意到，鹿会嗅并舔一个不熟悉的擦痕，这表明小树上的这种视觉标记在鹿的社交生活中起着重要的沟通目的。

However, biologists also noted that deer sniff and lick an unfamiliar rub, which suggests that this visual mark on a small tree plays an important communication purpose in the social life of deer.

鹿的额头上的腺体也有一种气味，当雄鹿擦痕产生时，这种气味就会转移到树上。

Buck rubs also have a scent produced by glands in the foreheads of deer that is transferred to the tree when the rub is made.

这些气味使雄鹿擦痕成为鹿之间进行嗅觉交流的重要手段。

These odors make buck rubs an important means of olfactory communication between deer.

几十年前，一项对圈养成年骡鹿的研究证明了嗅觉交流（使用气味进行交流）在鹿生活方式中的重要性，该研究指出，雄性鹿会用额头摩擦树枝，特别是在秋天临近的时候。

The importance of olfactory communication (using odors to communicate) in the way of life of deer was documented by a study of captive adult mule deer a few decades ago, which noted that males rubbed their foreheads on branches and twigs, especially as autumn approached.

十年后，另一项研究报告说，成年雄性白尾鹿在发情前和发情期间表现出额头摩擦（的行为）。

A decade later another study reported that adult male white-tailed deer exhibited forehead rubbing just before and during the rut.

研究发现，当白尾鹿摩擦时，它会沿着小树的垂直方向移动鹿角和前额腺体。

It was found that when a white-tailed buck makes a rub, it moves both antlers and forehead glands along the small tree in a vertical direction.

这种额头摩擦行为与雄鹿额头上发现的改良气味腺体中高度的腺体活动相一致；腺体活动导致成年雄鹿的额头毛皮（毛发覆盖）明显比雌性或年轻雄鹿颜色深。

This forehead rubbing behavior coincides with a high level of glandular activity in the modified scent glands found on the foreheads of male deer; the glandular activity causes the forehead pelage (hairy covering) of adult males to be distinctly darker than in females or younger males.

雄鹿前额在摩擦擦痕上的摩擦，可能会向同一物种的其他成员发送大量信息。

Forehead rubbing by male deer on buck rubs presumably sends a great deal of information to other members of the same species.

第一，沉积在擦痕上的化学物质提供了关于动物个体身份的信息；没有两种哺乳动物会产生相同的气味。

First, the chemicals deposited on the rub provide information on the individual identity of an animal; no two mammals produce the same scent.

例如，我们都知道，狗是通过嗅觉来识别对方的。

For instance, as we all know, dogs recognize each other via smell.

第二，因为只有雄鹿才会摩擦，所以雄鹿擦痕及其相关的化学物质表明了产生摩擦的鹿的性别。

Second, because only male deer rub, the buck rub and its associated chemicals indicate the sex of the deer producing the rub.

第三，年龄越大、越占优势的雄鹿会产生更多的雄鹿擦痕，并可能在给定的摩擦上沉积更多的腺体分泌物。

Third, older, more dominant bucks produce more buck rubs and probably deposit more glandular secretions on a given rub.

因此，许多标记良好的摩擦的存在表明了年龄较大、地位较高的雄性通常就在附近，而不仅是简单地粗略衡量给定地区的相对鹿的数量。

Thus, the presence of many well-marked rubs is indicative of older, higher-status males being in the general vicinity rather than simply being a crude measure of relative deer abundance in a given area.

雄鹿摩擦时发出的嗅觉信号所传递的信息，使其与其它鹿类的某些听觉信号产生了相同的社会效果，比如公麋鹿的号角声。

The information conveyed by the olfactory signals on a buck rub make it the social equivalent of some auditory signals in other deer species, such as trumpeting by bull elk.

因为雄性和雌性的白尾鹿都会通过气味和舔舐来回应雄鹿的擦痕，所以擦痕可能还有一个非常重要的附加功能。

Because both sexes of whitetails respond to buck rubs by smelling and licking them, rubs may serve a very important additional function.

尤其是对较新鲜的雄鹿擦痕（产生不到两天）来说，成年雌性比年长的母鹿更常光顾（这些擦痕）。

Fresher buck rubs (less than two days old), in particular, are visited more frequently by adult females than older rubs.

鉴于这一行为，有人提出，新鲜的雄鹿擦痕中存在的化学物质可能有助于生理上诱导和同步这些访问擦痕的雌性动物的生育能力。

In view of this behavior it has been suggested that chemicals present in fresh buck rubs may help physiologically induce and synchronize fertility in females that visit these rubs.

这对涉猎广泛的鹿来说是一个明显的优势，特别是对于在秋季发情期间，向几只成年雌性求爱的一只鹿而言。

This would be an obvious advantage to wide-ranging deer, especially to a when courting several adult females during the autumn rut.

白尾鹿产生的另一种视觉信号被称为雄鹿刮痕。

Another visual signal produced by white-tailed deer is termed a buck scrape.

雄鹿刮痕包括一块空地（直径约0.5米）和通过推开覆盖地面的树叶而形成的浅洼地；在雄鹿刮痕制造完成之后，鹿通常会在洼地中小便。

Scrapes consist of a clearing (about 0.5 meter in diameter) and shallow depression made by pushing aside the leaves covering the ground; after making the scrape, the deer typically urinates in the depression.

因此，就像雄鹿擦痕一样，雄鹿刮痕既是一种视觉信号，也是一种嗅觉信号。

Thus, like a buck rub, a scrape is both a visual and an olfactory signal.

通常在秋季落叶之后，也就是在发情期之前或期间，会产生雄鹿刮痕。

Buck scrapes are generally created after leaf-fall in autumn, which is just before or during the rut.

雄鹿刮痕通常处在开阔或显眼的地方，例如沿着鹿的踪迹。

Scrapes are usually placed in open or conspicuous places, such as along a deer trail.

大多数是由年长的雄性制造的，尽管雌性和年轻的雄性（2.5岁或更小）偶尔会制造这种雄鹿刮痕。

Most are made by older males, although females and younger males (2.5 years old or less) occasionally make scrapes.

The word “conspicuous” in the passage is closest in meaning to

According to paragraph 1, why are small red maple trees ideal for buck rubs?

The studies of forehead rubbing by deer described in paragraph 3 showed that

The word “exhibited” in the passage is closest in meaning to

Why does the author mention that “dogs recognize each other via smell”?

The word “crude” in the passage is closest in meaning to

What can be inferred from paragraph 4 about the trumpeting of bull elk?

According to paragraph 4, the buck rubs occurring in a given area reveal all of the following information about deer EXCEPT

The word “induce” in the passage is closest in meaning to

According to paragraph 5, which of the following is true about chemicals in buck rubs?

The word “termed” in the passage is closest in meaning to

According to the passage, in what way do buck scrapes differ from buck rubs?

Look at the four squares  that indicate where the following sentence could be added to the passage. This process can take a few hours to several days.  Where would the sentence best fit? Click on a square  to add the sentence to the passage.

Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

Buck Rubs and Buck Scrapes A conspicuous sign indicating the presence of white-tailed deer in a woodlot is a buck rub.  A male deer makes a buck rub by stripping the bark (outer layer) of a small tree with its antlers.  When completed, the buck rub is an obvious visual signal to us and presumably to other deer in the area.  A rub is usually located at the shoulder height of a deer (one meter or less above the ground) on a smooth-barked, small-diameter (16–25 millimeters) tree.  The smooth bark of small red maples makes this species ideal for buck rubs in the forests of the mid-eastern United States. Adult male deer usually produce rubs in late summer or early autumn when the outer velvet layer is being shed from their antlers. Rubs are created about one to two months before the breeding season (the rut). Hence for a long time biologists believed that male deer used buck rubs not only to clean and polish antlers but also to provide practice for the ensuing male-to-male combat during the rut. However, biologists also noted that deer sniff and lick an unfamiliar rub, which suggests that this visual mark on a small tree plays an important communication purpose in the social life of deer. Buck rubs also have a scent produced by glands in the foreheads of deer that is transferred to the tree when the rub is made. These odors make buck rubs an important means of olfactory communication between deer. The importance of olfactory communication (using odors to communicate) in the way of life of deer was documented by a study of captive adult mule deer a few decades ago, which noted that males rubbed their foreheads on branches and twigs, especially as autumn approached. A decade later another study reported that adult male white-tailed deer exhibited forehead rubbing just before and during the rut. It was found that when a white-tailed buck makes a rub, it moves both antlers and forehead glands along the small tree in a vertical direction. This forehead rubbing behavior coincides with a high level of glandular activity in the modified scent glands found on the foreheads of male deer; the glandular activity causes the forehead pelage (hairy covering) of adult males to be distinctly darker than in females or younger males. Forehead rubbing by male deer on buck rubs presumably sends a great deal of information to other members of the same species. First, the chemicals deposited on the rub provide information on the individual identity of an animal; no two mammals produce the same scent. For instance, as we all know, dogs recognize each other via smell. Second, because only male deer rub, the buck rub and its associated chemicals indicate the sex of the deer producing the rub. Third, older, more dominant bucks produce more buck rubs and probably deposit more glandular secretions on a given rub. Thus, the presence of many well-marked rubs is indicative of older, higher-status males being in the general vicinity rather than simply being a crude measure of relative deer abundance in a given area. The information conveyed by the olfactory signals on a buck rub make it the social equivalent of some auditory signals in other deer species, such as trumpeting by bull elk. Because both sexes of whitetails respond to buck rubs by smelling and licking them, rubs may serve a very important additional function. Fresher buck rubs (less than two days old), in particular, are visited more frequently by adult females than older rubs. In view of this behavior it has been suggested that chemicals present in fresh buck rubs may help physiologically induce and synchronize fertility in females that visit these rubs. This would be an obvious advantage to wide-ranging deer, especially to a when courting several adult females during the autumn rut. Another visual signal produced by white-tailed deer is termed a buck scrape. Scrapes consist of a clearing (about 0.5 meter in diameter) and shallow depression made by pushing aside the leaves covering the ground; after making the scrape, the deer typically urinates in the depression. Thus, like a buck rub, a scrape is both a visual and an olfactory signal. Buck scrapes are generally created after leaf-fall in autumn, which is just before or during the rut. Scrapes are usually placed in open or conspicuous places, such as along a deer trail. Most are made by older males, although females and younger males (2.5 years old or less) occasionally make scrapes.